Missing the texture paint mode stencil mask overlay when in texture paint mode for an object (blender 2.8)
You didn't pack the image. Anyway, I've created a new one. What you need is just to choose a brush with a higher Strength and another Blend mode. Also, be careful with your unwrapping, some faces are overlapping so when you paint on a part it will paint somewhere else. The easiest way, if you only paint in the 3D View, is to unwrap with Smart UV Project. If you also paint in the Image Editor, maybe mark seam and then choose the simple Unwrap mode.